natural gas

Natural gas burning on a gas stove Natural gas (also gas, methane gas or fossil gas) is a fossil fuel, naturally occurring in geological formations. Typically, the gas is a mix of gaseous hydrocarbons, primarily methane (95%), small amounts of higher alkanes, and traces of carbon dioxide and nitrogen, hydrogen sulfide and helium. Methane is a colorless and odorless gas, and, after carbon dioxide, is the second-greatest greenhouse gas that contributes to global climate change. Because natural gas is odorless, a commercial odorizer, such as methanethiol, that smells of hydrogen sulfide (rotten eggs) is added to the gas for the ready detection of gas leaks.

Natural gas is a fossil fuel that is formed when layers of organic matter (primarily marine microorganisms) are thermally decomposed under oxygen-free conditions, subjected to intense heat and pressure underground over millions of years. The energy that the decayed organisms originally obtained from the sun via photosynthesis is stored as chemical energy within the molecules of methane and other hydrocarbons. Most natural gas is collected from underground geological formations, often alongside other fossil fuels like coal and oil (petroleum). Natural gas is often a byproduct of petroleum production, where it can either be vented without burning, flared (burned off) or collected.